WASHINGTON -- Senate Republicans on Wednesday blocked $600 million in emergency funding intended to improve the monitoring of prescription drugs and help law enforcement combat heroin abuse.

In a 48-47 procedural vote, Republicans prevented the amendment from being attached to a larger bill aimed at fighting the heroin and opioid epidemic sweeping the U.S. The legislation, called the Comprehensive Addiction Recovery Act, would establish an interagency task force to create best practices for prescribing opioids, and shift federal officials toward prevention-driven drug policy and away from punishment.

The emergency funding provision would have allocated $230 million to law enforcement initiatives, including treatment alternatives to incarceration. Another $10 million would have gone to state and local law enforcement units that oversee communities with high levels of drug use.

Drug reform groups were not pleased with the hundreds of millions of dollars in the measure that would have gone toward enforcement. "CARA is clearly a step in the right direction, while the Democratic alternative looks like something out of the 1980s," said Bill Piper, a top official with the reformist group Drug Policy Alliance, which is typically more sympathetic to Democratic approaches.

The amendment, authored by Sen. Jeanne Shaheen (D-N.H.), also set aside $300 million for state programs focused on prevention, treatment and recovery, and for improving treatment for pregnant and postpartum women dealing with heroin or opioid addiction. The remaining funds would have helped the Centers for Disease Control and Prevention in its drug monitoring programs, and increased medication-assisted treatment in high-risk communities.

While the underlying bill is bipartisan and the product of three years of work between senators in both parties, Shaheen’s measure was seen as the one “controversial” amendment.

Senate Majority Whip John Cornyn (R-Texas) called it “duplicative.”

Republicans argued that millions of dollars were already appropriated to tackle heroin and opioid addiction in the omnibus spending bill passed in December. But Democrats wanted emergency funds to help communities grappling with the problem.

“The omnibus provided a modest boost to key federal programs, but it did not begin to address the magnitude of the opioid crisis,” Sen. Jeanne Shaheen said in a statement. “What the omnibus didn’t provide was a way to direct funding to first responders and treatment providers quickly. My amendment fast-tracks urgently needed resources specifically to those on the front lines battling this pandemic.”